Final answer:
In eukaryotes, promoters are recognized by transcription factors, which bind to DNA sequences such as the TATA box, CAAT box, and GC-rich boxes.
Step-by-step explanation:
In eukaryotic cells, promoter sequences are recognized by transcription factors. These transcription factors bind to specific DNA sequences within the promoters, enabling the attachment of RNA polymerase and the formation of the transcription initiation complex. Eukaryotic promoters are intricate and feature various conserved elements such as the TATA box, the CAAT box, and occasionally GC-rich boxes or octamer boxes.
The TATA box is a crucial component of eukaryotic promoters, typically located around -25 to -35 bases upstream of the transcription start site. It comprises an A-T rich sequence, like TATAAA, which helps to unwind the DNA due to the low thermostability of A-T bonds. Other regulatory elements like the CAAT box and GC box also play significant roles in promoter recognition by transcription factors.
In addition to the TATA box, transcription factors recognize and bind to these other boxes, facilitating the precise initiation of transcription. Different transcription factors might recognize different motifs within the promoter regions, varying the control over gene expression. The process ensures that only the genes necessary for a particular cell are active, avoiding random and high-rate transcription that is seen in prokaryotes without their specific sigma factors.